Lumen
Lumen (lm) is the unit for luminous flux. In other words, it is the amount of light that a point of light emits in all directions. So the brightness of a point of light is measured, independent of the direction of the light beam.
Lumen (lm) is the unit for luminous flux. In other words, it is the amount of light that a point of light emits in all directions. So the brightness of a point of light is measured, independent of the direction of the light beam.